Calcium salts, distillation

A method used in industry for ketonization of aliphatic acids is to pass the carboxylic acid vapors at about 300° over calcium, barium, or thorium oxide catalysts, and this is in principle also a calcium salt distillation. 

Ethyl S-n-butyl xanthate. Use 32 g. of potassium ethyl xanthate, 37 g. (23 ml.) of n-butyl iodide (Section 111,40) and 50 ml. of absolute ethyl alcohol. Reflux on a water bath for 3 hours. Pour into 150 ml. of water, saturate with salt (in order to facilitate the separation of the upper layer), remove the upper xanthate layer, wash it once with 25 ml. of saturated salt solution, and dry with anhydrous calcium chloride or anhydrous calcium sulphate. Distil from a 50 ml. Claisen flask under reduced pressure. Collect the pale yellow ethyl S-n-butyl xanthate at 90-91°/4 mm. The yield is 34 g. 

Dissolve the solid in 700 ml. of water in a 1500 ml. round-bottomed flask, and add a solution of 88 ml. of concentrated sulphuric acid in about 200 ml. of water until the liquid has a distinct odour of sulphur dioxide sufficient heat will be liberated in the neutralisation to cause the solution to boil. Immediately steam distil the liquid (Fig. II, 40, 1 it is better to use the apparatus shown in Fig. II, 41, 3) until a sample of the distillate gives only a slight precipitate with bromine water. About 700 ml. of distillate should be collected. Saturate the steam distillate with salt, extract the dl with ether, dry the extract with a little anhydrous magnesium or calcium sulphate, distil oflF the ether (compare Fig. II, 13, 4, but with a 50 ml. Claisen flask replacing the distilling flask) and distil the residue under diminished pressure. Collect the p-cresol at 95-96°/15 mm. the colourless liquid solidifies to a white crystalline solid, m.p. 31°. The yield is 24 g. 

Place 45 g. (43 ml.) of benzal chloride (Section IV,22), 250 ml. of water and 75 g. of precipitated calcium carbonate (1) in a 500 ml. round-bottomed flask fltted with a reflux condenser, and heat the mixture for 4 hours in an oil bath maintained at 130°. It is advantageous to pass a current of carbon dioxide through the apparatus. Filter off the calcium salts, and distil the filtrate in steam (Fig. II, 40, 1) until no more oil passes over (2). Separate the benzaldehyde from the steam distillate by two extractions with small volumes of ether, distil off most of the ether on a water bath, and transfer the residual benzaldehyde to a wide-mouthed bottle or flask. Add excess of a concentrated solution of sodium bisulphite in portions with stirring or shaking stopper the vessel and shake vigorously until the odour of benzaldehyde can no longer be detected. Filter the paste of the benzaldehyde bisulphite compound at the pump... 

To purify commercial diethyl carbonate wash 100 ml. of the compound with 20 ml. of 10 per cent, sodium carbonate solution, then with 20 ml. of saturated calcium chloride solution, and finally with 30 ml. of water. Dry the ester by allowing it to stand for 2 hours over 5 g. of anhydrous calcium chloride (prolonged contact results in combination of the ester with the salt), distil and collect pure diethyl carbonate at 125-126°. 

Hydrolysis of Peroxycarboxylic Systems. Peroxyacetic acid [79-21-0] is produced commercially by the controlled autoxidation of acetaldehyde (qv). Under hydrolytic conditions, it forms an equiHbrium mixture with acetic acid and hydrogen peroxide. The hydrogen peroxide can be recovered from the mixture by extractive distillation (89) or by precipitating as the calcium salt followed by carbonating with carbon dioxide. These methods are not practiced on a commercial scale. Alternatively, the peroxycarboxyHc acid and alcohols can be treated with an estetifying catalyst to form H2O2 and the corresponding ester (90,91) (see Peroxides and peroxy compounds). 

Charcoal is generally satisfactorily activated by heating gently to red heat in a crucible or quartz beaker in a muffle furnace, finally allowing to cool under an inert atmosphere in a desiccator. Good commercial activated charcoal is made from wood, e.g. Norit (from Birch wood), Darco and Nuchar. If the cost is important then the cheaper animal charcoal (bone charcoal) can be used. However, this charcoal contains calcium phosphate and other calcium salts and cannot be used with acidic materials. In this case the charcoal is boiled with dilute hydrochloric acid (1 1 by volume) for 2-3h, diluted with distilled water and filtered through a fine grade paper on a Buchner flask, washed with distilled water until the filtrate is almost neutral, and dried first in air then in a vacuum, and activated as above. To improve the porosity, charcoal columns are usually prepared in admixture with diatomaceous earth. 

Sulphate SO4 Increased solid content Combines with Ca to form calcium sulfate salt Distillation Demineralization... 

In addition to the Friedel-Crafts leaction, the aromatic ketones may be obtained by distilling the calcium salt of the... 

The above series of alcohols are exceedingly difficult to manufacture, hence their expense. The general method of their preparation would theoretically be by distilling the calcium salts of the corresponding fatty acid with calcium formate, in vacuo. This would yield the corresponding aldehyde, which on reduction would yield the corresponding alcohol. In practice, however, many technical difficulties arise, and special processes have to be used which are kept carefully as trade secrets. 

The barium or calcium salt of the corresponding acid may be distilled with barium formate —... 

Citral can also be obtained in a pure state by distilling a mixture of the calcium salt of geranic acid with calcium formate, according to the usual method tor the production of aldehydes. 

The acid, without drying, is suspended in about 200 cc. of distilled water and with vigorous stirring, cautiously (Note 3) treated with 25 per cent sodium hydroxide solution until dissolved and the solution reacts neutral to litmus. The solution is then filtered through folded filter paper which should be free from soluble calcium salts, otherwise the filtrate will remain clouded by a suspension of the calcium salt. The clear, faintly yellow or colorless filtrate is then vigorously stirred and treated with 1.5 volumes of 95 per cent alcohol. Crystallization is induced by rubbing with a rod and then an additional volume of alcohol is added. The mixture should be allowed to cool to about 200 and stand for at least two hours to complete the precipitation of the salt, which is then filtered by suction and washed thoroughly with 85 per cent alcohol. The salt is then air-dried. The yield is 73-77 g. (38-40 per cent of the theoretical amount). 

Continuous recovery requires AA crystals having an average diameter of ca. 40-50 nm.5 Such crystals are obtained by continuously introducing die hot hydrolysate containing 10-20% AA into an agitated crystallization vessel while maintaining an average temperature of 20-30°C. The slurry obtained from the crystallization vessel is filtered to collect die AA crystals, and the filtrate which contains the HMDA acid salt is continuously neutralized with calcium hydroxide. The calcium salt formed is removed by filtration, and the HMDA in the filtrate is isolated by distillation. 

Creosol (also called 2-methoxy-jb-cresol, 4-methylguaiacol, and 3-methoxy-4-hydroxytoluene) has been obtained by the fractionation of beach creosote tar,4 by the reduction of vanillin by electrolytic methods,6 6 by hydrogen and palladium on charcoal or barium sulfate,7 8 with hydrazine,9 and by amalgamated zinc and hydrochloric acid.3 10 11 It has also been prepared by methyl-ation of 4-methylcatechol with methyl iodide 12 13 or with methyl sulfate 14 and is reported to be formed by the distillation of the calcium salt of 3-methoxy-4-hydroxyphenylacetic acid.16... 

A. Triethyl oxalylsuccinate. In a 2-1. three-necked flask equipped with a sealed stirrer and a reflux condenser bearing a calcium chloride drying tube is placed 356 ml. (276 g., 6.00 moles) of anhydrous ethanol (Note 1). Sodium (23 g., 1.0 g. atom) is added in small portions at a rate sufficient to keep the ethanol boiling. External heating is required to dissolve the last portions of the metal. After all the sodium has dissolved, the excess ethanol is removed by distillation at atmospheric pressure as the mixture becomes pasty, dry toluene is added in sufficient amounts to permit stirring and to prevent splattering of the salt. Distillation and addition of toluene is continued until all the ethanol is removed and the contents of the flask reach a temperature of 105° (Note 2). The sodium ethoxide slurry is cooled to room temperature and 650 ml. of anhydrous ether is added, followed by 146 g. (1.00 mole of diethyl oxalate. To the yellow solution there is added 174 g. (1.00 mole) of diethyl succinate, and the mixture is allowed to stand at room temperature for at least 12 hours. 

Indanone was first prepared by distillation of the calcium salt of o-phenylenediacetic acid2 3 and, more recently, by the action of acetic anhydride on its potassium salt.4 It has been obtained by the dilute sulfuric acid-catalyzed hydrolysis and decarboxylation of 2-iminoindan-l-carboxylate6 and ethyl 2-indanone-l-carboxylate.6 2-Indanone is commonly obtained by acid-catalyzed dehydration of an indene glycol,7 8 as illustrated in this preparation. Indene glycol has been obtained from indene via the bromohydrin.9-12 The most recent preparation of 2-indanont is by Curtius degradation of 2-indenecarboxylic acid.13... 

The mixed calcium salt is dissolved in ZN nitric acid, using 15ml of the latte for every 2g of the material The clear solution is diluted to double its volume with distilled water and fig of silver nitrate (for each 2g portion of calcium salt) is dissolved in the liquid. The mixture is stirred until the beige precipitate settles out. This is filtered, the silver hypophosphate rinsed with acetone, and the product is dried in warm air. It is only slighter photosensitive and may be stored in clear bottles in artificial light for extended periods of time. 

Reaction XXI. (a) Dry Distillation of the Barium or Calcium Salt of a Fatty Add with Barium or Calcium Formate.—This is one of the methods by which aldehydes may be obtained from acids. Like most dry distillations, the yields are poor, and the method is seldom used. 

Cyclopentanone has been prepared from adipic acid by distilling the calcium salt,1 heating alone 2 or with acetic anhydride,3 or in the presence of various catalysts such as barium hydroxide,4 thorium oxide,5 manganous oxide,5 uranium nitrate,6 ferrous sulfate 6 and others.7... 

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